I drive my car in 6th gear going 40-45mph and above and the RPM is around 1.5K and I do it because it saves gas.

Is that bad for my clutch/pressure plate and flywheel? Does it wear them out in any way doing that?

and does anyone know if there is a way to check to see if the clutch is fully engaged while in gear? I'm thinking that mine doesn't engage all the way and when I put a lot of load on it in 6th gear going 40-45mph is slips and it wears out.

if the clutch slips for more than 2 seconds it is going to smell like crap.
To asnwer ur question: Yes it is okay to have the car in 6th gear at 40mph as long as ur not trying to accelerate. For maintaining speed it is perfectly fine.
The only time there is any kind of negative affect is when u try to accelerate in 6th gear going 35-40mph, which would put some stress on ur engine and nothing else.

That's what people been telling me.

My OEM clutch went out at 52k and I thought that what I was doing made it fail early.

You should be fine. Owners manual says you can shift to 6th gear at 33mph, though that's just too low for me personally....I've cruised 40-45 in 6th occasionally, no problems.

I ride in 6th gear all the time if i know ill be cruising for a while. I also "skip" gears when on the street, ie 1st to 3rd, 3rd to 5th, etc

Pretty much the only time your clutch will wear is when it is slipping. If you are off of the pedal, there is a direct connection between the motor and wheels so nothing is slipping. I don't really buy that accelerating from 40 in 6th gear will do any damage.

As for your slipping in 6th, I have no idea what that is. If the clutch were shot, you would first feel it when shifting to 2nd and maybe 3rd. Good luck, let us know if you figure it out.

BOuncing offf rev won't do any damage either, but it will speed up the engine wear, same thing applies to pressing that gas more than half way trying to accelerate in 6th gear going 40mph.